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The mosquito that carries Zika is most active at predawn and sunset

All spraying must take place at those times

(CNN)A plane flying over Miami Beach on Friday conducted aerial spraying for mosquitoes carrying the Zika virus, despite concerns over possible effects that the insecticide naled may have on health and the environment.

Since the mosquito that carries Zika is most active at predawn and at sunset, all spraying must take place at those times.

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"Aerial spraying using Naled and other insecticides has been used in many populated areas of the continental United States, including Miami, Tampa and New Orleans to help control mosquitoes," the CDC said on its website.

Peter Beach, who describes himself as a closet anarchist, condemned the spraying.

South Beach resident Peter Beach, 62, said he is really angry about the spraying. Beach, who described himself as a closet anarchist, voiced contempt for the EPA and CDC approval of naled, the main chemical in the insecticide Dibrom.

"This is a toxic substance that kills everything," he said. "You think these tourists on the beach know they are lying on sand that was hit with a toxic carcinogenic hours earlier? No way."

The US has used naled since the 1950s, and sprays it on about 16 million acres nationwide annually. Health officials use it to prevent mosquitoes after disasters such as hurricanes and floods, according to the CDC.

Naled breaks down swiftly in water and sunlight, and its chemicals don't cause health problems in people or pets if used in small quantities, according to the CDC.

A few days later, in an unprecedented move, the CDC announced a travel warning, advising pregnant women not to visit that area. Authorities launched aggressive mosquito-control measures, including spraying in the area.

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Last month, the CDC advised pregnant women not to travel to an area of Miami Beach limited to 1½ square miles.

Pregnant women are at greatest risk because the virus can have devastating consequences for an unborn baby, including the birth defect microcephaly and other neurological disorders, as well as miscarriage and stillbirth among women infected while pregnant.

In addition to human health, critics say naled kills pollinators and wildlife, and is toxic to the environment.

South Carolina beekeeper Juanita Stanley recently lost more than 3 million bees when Summerville officials aerially sprayed a small area of the town for Zika-carrying mosquitoes.

"In the summertime, the bees are already out at dawn, when aerial spraying is recommended," said entomologist Jeffrey Harris, who runs the Honey Bee Extension and Research Program for Mississippi State University. "So spraying in the morning is the worst thing they can do for bees."